To establish a fair competition between racing vehicles is not an easy task, if different types of engine are allowed to participate (within the same class). In the Motorsports world there are several Championships where the regulations leave to the project manager substantial freedom in the vehicle-engine layout definition: The 2002 World Offshore Class I Championship (WOCC) seems to be an excellent example, since both gasoline and diesel (naturally aspirated and turbocharged) engines are admitted to race.
The paper presents a power output comparison method that could be useful both for the organizers to establish a fair competition as well as for the racing engineers to decide what's the optimal layout.
Since the analysis regards the maximum power, BMEP and engine speed have to be evaluated under such condition for the engines to be compared. This operation is done on a statistical basis, which means that the results of the analysis are not numerically exact, but they offer useful tools to make a meaningful comparison.
The engine performance is then calculated, considering the limitations imposed by the WOCC regulations. The power deliverable by diesel turbocharged engines is found to be much higher than that obtainable from other engines allowed to participate in the same class. Several solutions have been considered in order to obtain the same power output from different engines, and therefore to re-establish a fair competition.
A reduction of the turbocharging pressure (through a standard pop-off valve), a limitation of the intake air mass flow (through a Venturi-type duct or a diaphgram), and a limitation on fuel consumption, may all be used to reduce the gap. The method allows to propose changes in the regulations and to determine reliable values for performance limitation parameters.